Inflatable rubber article



Jan. 17, 1939. W, B KER 2,143,837

INFLATABLE RUBBER ARTICLE Filed July 3, 1935 INVENTOR $50 955 14 BECKERATTORNEY Patented Jan. 17, 1939 amt?!) f p J t i N L A E v f aGeoi-gejwlBecker, Silver Lake, Ohio, aisignmsyf v mesneufassignments,

' Ohio rubber tarticlespxsuch as inner? tubes for fpneu matictlres, andto improved: procedurefor incorporatingsaidvalve-stems inth'extubestructures. The invention is cfwprimarynutility invthe mounting tof.metal :valve stems iin inner, tubes,

1 especially inner tubes of large size which have P 1 The valve stemdescribed is arranged to be "mountedin thewall' of an inner tube, aportion Tof'thedatter bingshown at l9 in the drawing.

As-hereinbefore stated,the invention is especially advantageous in innertubes of large size, where:

in' the tube wallis' relatively thick as shown.

L. In preparing an unvulcanized tubeto, receive the tvalvestem,.zasphericalwsegment of stock'is cut ,from: the outer face ofthe tube wall, adjacent 1 an: end thereof, whichsegment is substantiallyor nearly the same ,size and, shape as the flange I4 relatively,tthickwwalls. 4

r The chief objectstof =the invention are to prof vide an improved innertube=structure; to pro ,videan improved valve-2 stem mounting in, aninner tube to prevent the valve stem: from "being torn-therefrom; topreventlea'kage of-air from the tube at the :placewhere the valve stem'is 1 mounted therein; to a provide a superior valve stem mounting in airinner.v tube without greatly ,20 increasing the thickness of thetube-wall thereat; and to provide an improved method wherebtheforegoingobl'ects are achieved.

Of the accompanying drawing: Figure 1 is a side elevation of a metalvalve stem provided with a rubber 'baseflangeconstltuting a part of theinvention;

Figure 2 is a plan view thereof; Figure 3 is a fragmentary plan view ofa rubber tube wall and a valve stem mounted therein,

before the tube is vulcanized;

Figure 4 is a section on the line H of Fi ure Figure 5 is a sectionsimilar to Figure 4, after the tube has been vulcanized; and

Figure 6 is a fragmentary, transverse section through a pneumatic tireandtire base, and the improved inner tube mounted for use within thetire.

Referring to the drawing, I0, is a metal valve stem of known orpreferred construction, which valve stem is formed at its bottom with anenlarged flange or head H, and has a small smooth region i2 on itsstructure immediately above said head, and a threaded portion, [3immediately above said smooth region. The head H is completely encasedand vulcanized into a fully vulcanized rubber base flange N thatpreferably has the shape of a spherical segment, being circular in planand having a plane top face Ma that is normal to the axis of the valvestem I0 tube wall.

a cavity 2|.

to'lhe Firestone Tire 4a ba pomnanajh ea ohi rr a i ii t H .itaiatot,Iuly3, 1935, semrmfzacia Thisinvention relates.v to inflatable rubberarticles. and to methods of t making the same, and more especially itrelates to improvements in the mounting ofvalvestemsdnthewalls-of'inflatable p of separationof the parts isobviated. Theshal- 5 low recesses indicated at; l5, I5 of'the drawing jare formed by the' lugs that support the valve stem in the mold whiletheflange .II is being molded and vulcanized thereontofland have nowiththeair passage ll ofthe valve stem. The

" rubber'oi the baseflange ll isarelatively tough and-stiff composition,wherebya fluid-tight union with the head II is effected-,an'dthepossibility other function in the invention. Pi 10 of the ;valvestem, thus forjmingta concavity 2| v in said. tube, wall. Preferably thedepthot the concavity 2| is about half the thickness of the Thereafteran aperture 22 is formed 25 in the tube wall, concentric with the axisof con- After the faceof the tube including the concavity 2|v has beenwiped with a suitable hydrocarbon rubber solvent, the valve stemstructure shown in Figures land 2 is mounted there- 30 comprising aplurality of piles of concentric, cir- 35 cular sheet rubber discs ofdifferent diameters arranged with stepped or offset margins whereby thesaid patch is thinner at its marginal portion than in its centralportion. Said central region of the patch is of greater diameter thanthe/ flange l4, and at its middle the patch flts snugly about the s oothregion l2 of the valve stem.

After th structure is assembled as described, and shown in Figures 3 and4, the respective ends of the tube I8 may be spliced together in theusual manner and the tube vulcanized in a mold underheat and internalpressure as is well understood by those skilled in the art. During thevulcanizing operation the plies of the patch 23 50 coalesce with eachother and with the tube I9 where they contact the latter, to form ahomogeneous, unitary structure, and patch and tube wall becomeadhesively united to flange I4 by vulcanization, whereby the flange isfirmly emseparation I therefrom prevented.

As, will'be seenby reference to Figure 5 which ishowsrthe-valveinstallation after vulcanization,

theflnished tube presents a substantially smooth inner and outer surfacein the region oi the'va'lve stem., ,The rubber composition from whichthe tube Isis made, and the rubber of the patch 23, when vulcanized isrelatively flexible and elastic as compared to the composition of theflange ll, yet the thin flexible margin of the latter prevents suchsharp "flexure at the juncture of the flange and tube stock as mightstrain the tube or tend to-cause separation 01 flange and tube stock;Moreoventhe relatively stifl composition 0! the flange'lli moreeffectively prevents the head lloi-thewalve stem from being pulled fromthe tube than would be the case'ii said head were -embedded in theordinary soft and elastic tube stock. Obviously, the shape o! the flangel4 may beother than circular ii" desired: for, ex-' ample, it might beelliptical, or it might be .rhombus-shaped iii-plan. .2

.In 'Figure, 6' the improved inner tube l8 is shown'mounted in apneumatic tirecasing and the latter-mountedupon the usual tire rirn 25,the valve stem It extendingthrough an anfi fture 21 in the rimand beingsecuredfin place byz'a nut 28 threaded onto itsv threaded portion 13.Mounted uponsaid'threaded portion II, between the "innertube l! andthe=rim 28, is an annular rubberwa'sher 29. that replaces theusual'bridge clip. Thewasher 29'has a beveled peripheral margin asshown, andis mounted with :its large diameter adjacent the tube so-thatit fits nicely between the 'toes of the tire beads,. The washer 28limits the extent-to which, the tube'wall and. v I valve stem head itcan be drawn down between the tire b'eads,=sndthus prevents such sharpflexure or the rubber structure abou as might'airriure said structure.

Modification-i: may-be resorted to without us.

-- parting: irom thespirit oi the invention or the scope oitheappcndedclaims." j i surfaces thereof.

t said head il v g amass? bedded within'the. tube wall and subsequent 2.An inner tube comprising a wall 0! relative- 1y flexible and elasticrubber composition, and a valve stem formed with a base flange ofrelatively stifl, tough rubber, said base flange having theshape'ofaspherical segment and being vulcanized entirely within the wallof the tube with its convex iace disposed innermost.

3, A valve stem comprising a tubular metal structure formed with anenlarged head at its base, and a base flange oi vulcanized, stiff, toughrubber composition encasing said head, said flange having the shape of aspherical segment, the metal'structure projecting from the flat face oisaid flange;

'4. A valve stem-comprising atubuiar structure having 'a'base flange ofvulcanized rubber, said 'flangehaving' the shape of a spherical segment,

the tubular portion :0! the stem projecting from the flatiace 01' saidflange.

5. A valve stem comprising' a tubular structure having a base flange oivulcanized rubber, said flange having a completely convex bottom face,

and lhavingaflat top face from which the tubular structure projects.

6. An inner tube'comprising a wall or relative- ,ly' flexibleand'elastic rubber composition, a metal valve stem having an enlarged headat its base, and-a flange, of rubber composition vulcanized to andcompletely encasing said head, said flange being vulcanized within thetube wall between the inner and outer surfaces thereof.

GEORGE w; nacx'ma.

